Lithograph offset machine plate clamp



Feb 18, 1936. i e. P. DAMINAITIS 2,031,559

LITHOGRAPH OFFSET MACHINE PLATE CLAMP Filed Feb. 25, 1955 Patented Feb.18, 1936 UNITED STATES.

PATENT OFFICE LITHOGBAPH PLATE OFFSET MACHINE CLAMP This inventionrelates to ,novel and improved clamping means for securing flexiblesheets or plates in even and firm contact with a printing presscylinder, and is particularly adapted for securing the zineplates to thecylinders of offset lithographing presses.

The main object of the invention is to provide a simple and novel clampmechanism for such printing plates which will be convenient to operateand which will stand the strain and hold the plate wrapped around thecylinder surface with a uniform tension in all directions so as toprevent any wrinkles on the surface of the flexible plate and insureaccurate printing.

A further object of the invention is to provide a clamp used as a holderon each of two ends of a lithographic plate for the purpose of attachingthe plate around the steel cylinder of a lithographic ofiset machine.

A still further object of the invention is to provide a slot runningthrough the length of the clamp for inserting the lapped end of theplate therein and a series of eyelets at the outward edge of the clampfor engaging the cylinder.

A still further object of the invention is to lap the ends of the plateand form a double thickness for locking the ends thereof in the slot ofthe clamp.

A still further object of the invention is to form 30 the clamp in twosections held together by the riveted ends of the eyelets.

' A still further object of the invention is to form one portion of theslot wider than the other portion to accommodate the double thickness of35 the lapped end.

A still further object of the invention is to slidably hold, the ends ofthe plate in the clamp. With the above and other objects in view as willbe presently understood, the invention consists in general of certainnovel details of con- 55 are held in place.

Figure 5 is a fragmentary view of the plate showing the lapped edge.

Figure 6 is a fragmentary view showing the end of the plate attached tothe top of the roller of the lithographic machine and Figure 7 is asimilar view as Figure 6 but showing the plate attached to the bottom ofthe roller.

In the embodiment of the invention' disclosed in the accompanyingdrawing thereis a plate member I to which is applied in the well known10 manner the characters to be lithographed. The plate is of thinresilient metal and is wrapped around the steel roller 2 of a standardlithograph offset machine. At both ends of the plate are clamps 3. forattaching the ends of the plate to 15 the roller. The rollerof a machineof this kind is provided at the top andbottom with the usual fixtures lrunning lengthwise with the roller. Each of these fixtures includes aseries of hooks 5 to which the U-shaped eyelets 6 at the ends 20 of theclamp are attached.

The'clamp is preferably made from two lengths of material 1 and 8 heldtogether at the ends by the rivets 9. The remainder of the cooperatinglengths are held together by the ends ill of the said eyelets 6. As bestseen in Figure 4 the ends of the eyelets are provided with a knee bendand pass through both of the lengths l and 8 of the clamp and areriveted in place at the extreme ends as at ll.

l2 of the eyelets a small amount of solder 13 may be introduced in orderto prevent the parts from becoming loose.

In the portion 8 of the clamp a longitudinal slot I I is provided tohold the end of the clamp. The slot has a widened portion l5 and anarrowed portion IS. The widened portion of the slot is approximatelytwice the width of the narrowed portion and is'adapted to house thelapped end I! of the plates and the narrow por- 40 tion is adapted toaccommodate the body of the plate. As the width of the narrowedportionis less than the combined thickness of the lapped end ll of theplate it is obvious that the said end cannot be pulled through the slot.7

The outward ends of the slots are preferably bevelled as at ill in orderto make the insertion of the plate easier. The plate is in noway fixedto the clamp and can easily be slipped out from the groove. 7

There has thus been provided a simple and eflicient device of this kindfor the purpose specifled.

It is obvious that changes may be made in the form and construction ofthe invention without At the curved portion 30 departing from thematerial principle involved. It is therefore not desired to confine theinvention to the exact form herein shown and described but it is desiredto include all forms which come within the scope of themppended claims.

Having described my invention,'I claim:

1. In a device of the class described, a plate adapted to be wrappedaround the surface of a roller, said plate having lapped ends, clamps atthe ends of said plate, said lapped ends fitting in-said clamps, andmeans to attach said clamps t o said roller, saidmeans comprising a setof eyelets at the sides of said clamps adapted to engage a set of hookson said roller.

2-. In a device oi the class described, a plate adapted to be wrappedaround the surface of a roller, said plate having lapped ends, clamps atthe ends of said plate, said lapped ends slidably fitting in saidclamps, and means to attach said clamps to said roller, said meanscomprising a set of eyelets at the sides of said clamps adapted toengage a set of hooks on said roller.

3. In a device of the class described, a clamp provided with alongitudinal slot, said slot having a wide and narrow portion, a set ofU-shaped eyelets at the side of said clamp, and a plate fitting at itsend in said slot;

4. In a device of the class described, a. clamp provided with alongitudinal slot, said slot having a wide and narrow portion, a set ofU-shaped eyelets at the side of said clamp, and a plate fitting at itsend in said slot, said end of the plate having a thickened portion whichfits in the wide portion of the slot.

5. In a device of the class described, a. plate adapted to be wrappedaround the surface of a roller, said plate having lapped ends, clampsmade of two parts and provided with a slot in one o! the parts, saidlapped ends fitting in said slot of said clamps, and means to attachsaid clamps to said roller, said means comprising a set of eyelets atthe side of said clamps adapted to engage a set of hooks on said roller,the ends of said eyelets passing through said clamps for holding theparts of the clamp together.

6. In a device of the class described, a plate adapted to be wrappedaround the surface of a roller, said plate having lapped ends, clampsmade 01 two parts and provided with a slot in one of the parts, saidlapped ends slidably fitting in said slot of said clamps, and means toattach said clamps to said roller, said means comprising a set ofeyelets at the side of said clamps adapted to engage a set of hooks onsaid roller, the ends of said eyelets passing through said clamps forholding the parts'of the clamp together.

- 7. In a device or the class described, a clamp made of two parts, alongitudinal slot in one of the parts, said slot having a wide andnarrow portion, a set of U-shaped eyelets protruding outward of saidclamp, the ends of said eyelets passing through both of said parts, anda plate fitting at its end in said slot.

8. In a device of the class described, a clamp made of two parts, alongitudinal slot in one 01 the parts, said slot having a wide andnarrow portion, a set of U-shaped eyelets protruding outward of saidclamp, the ends of said eyelets being bent, said bent ends passingthrough both of said parts, and a plate fitting at its end in said slot,said end oi! the plate having a thickened portion which fits in the saidwideportion of the slot. Q

GEORGE P. DAMINAI'I'IS.

